The Antibacterial Activities and Characterizations of Biosynthesized Zinc Oxide Nanoparticles, and Their Coated with Alginate Derived from Fucus vesiculosus

Zinc oxide nanoparticles have many advantages for nano-biotechnologists due to their intense biomedical applications. ZnO-NPs are used as antibacterial agents, which influence bacterial cells through the rupture of the cell membrane and the generation of reactive free radicals. Alginate is a polysaccharide of natural origin due to its excellent properties that are used in various biomedical applications. Brown algae are good sources of alginate and are used as a reducing agent in the synthesis of nanoparticles. This study aims to synthesize ZnO-NPs by using brown alga Fucus vesiculosus (Fu/ZnO-NPs) and also to extract alginate from the same alga, which is used in coating the ZnO-NPs (Fu/ZnO-Alg-NCMs). The characterizations of Fu/ZnO-NPs and Fu/ZnO-Alg-NCMs were determined by FTIR, TEM, XRD, and zeta potential. The antibacterial activities were applied against multidrug resistance bacteria of both gram-positive and negative. The results obtained in FT-TR showed there are some shifts in the peak positions of Fu/ZnO-NPs and Fu/ZnO-Alg-NCMs. The peak at 1655 cm−1, which assigned amide I-III, is present in both Fu/ZnO-NPs and Fu-Alg-ZnO-NCMs; this band is responsible for bio-reductions and stabilization of both nanoparticles. The TEM images proved the Fu/ZnO-NPs have rod shapes with sizes ranging from 12.68 to 17.66 and are aggregated, but Fu/ZnO/Alg-NCMs are spherical in shape with sizes ranging from 12.13 to 19.77. XRD-cleared Fu/ZnO-NPs have nine sharp peaks that are considered good crystalline, but Fu/ZnO-Alg-NCMs have four broad and sharp peaks that are considered semi-crystalline. Both Fu/ZnO-NPs and Fu/ZnO-Alg-NCMs have negative charges (−1.74 and −3.56, respectively). Fu/ZnO-NPs have more antibacterial activities than Fu/ZnO/Alg-NCMs in all tested multidrug-resistant bacterial strains. Fu/ZnO/Alg-NCMs had no effect on Acinetobacter KY856930, Staphylococcus epidermidis, and Enterobacter aerogenes, whereas there was an apparent effect of ZnO-NPs against the same strains.


Introduction
Bacterial infections are accredited as a severe health problem on a global scale. The need for more effective antibacterial agents is growing as a result of rising pathogenic strain outbreaks, antibiotic resistance, and new bacterial mutations. Since ancient times, zinc oxide has been used for its antimicrobial properties [1]. Nanomaterials with antibacterial action, such as metal nanoparticles and metal oxide nanoparticles, are currently considered a new line of defense against bacterial diseases. These materials have a unique antibacterial mechanism due to the nanoscale surface effect and small size effect, which primarily involves three points of view: release of metal ions or reactive oxygen species (ROS)

Alginate Extraction and Characterizations
The alginate extracted from F. vesiculosus was according to the methods of Hambali et al. [31]. The F. vesiculosus alginate was characterized according to previous research by Hamouda et al. [32].

Synthesis of Fu-Alg-ZnO-NCMs
F. vesiculosus sodium alginate in the amount of 1 gm was dissolved in 50 mL of D water at 40 • C, 0.037 gm of Fu-ZnO-NPs was added, and the mixture was agitated for 2 h before centrifuging, and drying the precipitate at 60 • C. The Fu/ZnO-NPs and Fu/Alg-ZnO-NCMs active groups were assessed using a Fourier transform infrared spectrometer (FT-IR) (JASCO Europe S.r.l., Cremella, Italy), FT-IR 5300 spectrophotometer; the FT-IR spectrum ranged between 4000 and 400 cm −1 .

X-ray Powder Diffraction (XRD)
The crystalline of nanoparticles was determined by an X-ray diffractometer (PAN Analytical X-Pert PRO, spectris plc, Almelo, The Netherlands); the Fu-ZnO-NPs and Fu-Alg-ZnO-NCMs size was determined using Scherrer's equation.
where λ = 0.1540 nm, k is the constant factor of 0.91, θ = diffraction angle in radians, and β = full width at half maximum (FWHM).

Zeta Potential Analysis
Zeta Potential Analysis provided details of the stabilization of Fu-ZnO-NPs and Fu-Alg-ZnO-NCMs and was measured by Malvern Zeta size Nano-Zs90 (Malvern, Westborough, PA, USA). The surface morphology and elemental composition of both Fu-ZnO-NPs and Fu-Alg-ZnO-NCMs were determined by using a field emission scanning electron microscope equipped with energy-dispersive spectroscopy (EDS) (JEOL JSM-6510/v, Tokyo, Japan).

Antibacterial Activities
The antibacterial activity of Fu/ZnO-NPs and Fu/Alg-ZnO-NCMs was displayed against multidrug-resistant bacteria (MDR) [33,34]. Gram-negative Klebsiella pneumoniae KY856924, Acinetobacter KY856930, E. coli KY856932, E. coli KY856933, Enterobacter KY856934, and Enterobacter aerogenes which have been isolated from different medical samples and identified as multidrug-resistant in a previous study [33,34], and Gram-positive control strains (Staphylococcus aureus ATCC 6538, Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228, Streptococcus mutans ATCC 25175). All the bacterial strains were cultured in nutrient broth at 37 • C for 24 h. A sterile cotton swab was used to spread the bacterial strains on Mueller-Hinton agar (MHA). Wells were made on the agar plates and filled with 100 µL of each Fu/ZnO-NPs and Fu/Alg-ZnO-NCMs (1 mg/mL). After 24 h of incubation at 37 • C, the clear zones were measured.

Statistical Analysis
Data of the effect of Fu/ZnO-NPs and Fu-Alg-ZnO-NCMs on different bacterial pathogens are presented as the mean standard error (SE) and were subjected to statistical analysis using one-way analysis of variance (ANOVA). The post hoc differences between means were tested by a Duncan multiple comparison test. Differences at p < 0.05 were considered significant. The results in Figure 1 and Table 1 (Figure 2). A band at 1655 cm −1 is present in both Fu/ZnO-NPs and Fu-Alg-ZnO-NCMs; this band is responsible for bio-reductions and stabilization of Fu/ZnO-NPs. The results also demonstrated that some peaks were shifted to higher-frequency positions, and others shifted to lower-frequency positions; those variations related to the change of composition of Fu/ZnO-NPs and Fu/Alg-ZnO-NCMs.

XRD of Fu/ZnO-NPs, and Fu-Alg-ZnO-NCMs
The results in Figure 3 and Table 2 show the X-ray diffraction analysis of Fu/ZnO-NPs bio-fabricated via F. vesiculosus. The results investigate nine sharp peaks at 2 theta 31.97, 34.57, 36.38, 47.74, 56.81, 63.33, 68.07, and 69.17 • correspond to lattice plane (hkl) 211, 220, 220, 221, 110, 110, 111, 111, 111, and 111. The major crystalline peak was obtained at 2 Theta 36.388 • , and the minor crystalline peak was obtained at 2 Theta 69.17 • . All peaks of Fu/ZnO-NPs are sharp peaks, which denote the Fu/ZnO-NPs are crystalline and also denote the purity of ZnO-nanoparticles. The crystal size has been intended from XRD analysis by the Debye-Scherrer equation, which in this work was equal to 29.9 nm with 100% intensity. The peaks of Zn-GNPs obtained by XRD are the sharp and crystalline structure of the nanoparticles [56]. The XRD diffraction patterns of Cystoseira crinite-ZnO-NPs were assigned at 2θ values of 31 nano-composites display a semi-crystalline nature [59]. The crystal size of Fu/ZnO-Alg-NCMs has been intended from XRD analysis by the Debye-Scherrer equation, which in this work was equal to 21.7 nm with 100% intensity. The average crystallite size for ZnO-NPs synthesized by leaf extracts of Eucalyptus globulus was 27 nm [60].     Figure 4 and Table 3 show the XRD patterns of Fu/Alg-ZnO-NCMs bio-synthesized via F. vesiculosus. The peaks were shown at four positions: 23.159, 29.457, 31.844, and 39.564, and reflect the (hkl) miller index at 110, 111, 111, and 211, respectively. The broad and sharp peaks denote Fu/ZnO/Alg-NCMs bio-synthesized via F. vesiculosus are semi-crystalline. The X-ray diffraction (XRD) results indicate that sodium alginate-ZnO nano-composites display a semi-crystalline nature [59]. The crystal size of Fu/ZnO-Alg-NCMs has been intended from XRD analysis by the Debye-Scherrer equation, which in this work was equal to 21.7 nm with 100% intensity. The average crystallite size for ZnO-NPs synthesized by leaf extracts of Eucalyptus globulus was 27 nm [60]. Polymers 2023, 13, x FOR PEER REVIEW 8 of 17

EDS Analysis of Fu/ZnO-NPs and Fu-Alg-ZnO-NCMs
The surface topography of bio-fabricated Fu/ZnO-Alg-NCMs and Fu/ZnO-NPs by F. vesiculosus was observed by Scanning Electron Microscopic ( Figure 5). The results demonstrate Fu/ZnO-NPs ( Figure 5a) have rough surfaces, and the particles are agglomerated, but in the case of Fu/ZnO-Alg-NCMs, Figure 5b shows the particles are irregularly spherical and impeded in alginate fibers as pointed by arrows. The EDS analysis in Figure 5c demonstrates the presence of elements Zn, C, and O by weight % of 30.08, 30.89, and 39.02, which confirmed the presence of Zn and oxygen. EdS analysis in Figure  5d demonstrates that the Zn is present in a low weight percentage (3.28%), and oxygen and carbon are present in high weight percentages (41.61 and 28.78, respectively), which confirmed the presence of alginate, and also the presence of Na and Ca proved the presences of alginate. Keshavarz et al. [61] reported the presence of a sodium peak in EdS analysis, proving the presence of alginate. The EDS spectra peak in both Fu/ZnO-NPs and Fu/ZnO-Alg-NCMs; the O peak appears at 0.5 KeV. Meanwhile, Zn peaks appear at 1 KeV, 8.6 KeV, and 9.5 KeV; these results are in agreement with [62]. Results of EDS spectra approve and verify the XRD result, which reveals the ability of F. vesiculosus marine macroalga to synthesize ZnO-NPs.

EDS Analysis of Fu/ZnO-NPs and Fu-Alg-ZnO-NCMs
The surface topography of bio-fabricated Fu/ZnO-Alg-NCMs and Fu/ZnO-NPs by F. vesiculosus was observed by Scanning Electron Microscopic ( Figure 5). The results demonstrate Fu/ZnO-NPs ( Figure 5a) have rough surfaces, and the particles are agglomerated, but in the case of Fu/ZnO-Alg-NCMs, Figure 5b shows the particles are irregularly spherical and impeded in alginate fibers as pointed by arrows. The EDS analysis in Figure 5c demonstrates the presence of elements Zn, C, and O by weight % of 30.08, 30.89, and 39.02, which confirmed the presence of Zn and oxygen. EdS analysis in Figure 5d demonstrates that the Zn is present in a low weight percentage (3.28%), and oxygen and carbon are present in high weight percentages (41.61 and 28.78, respectively), which confirmed the presence of alginate, and also the presence of Na and Ca proved the presences of alginate. Keshavarz et al. [61] reported the presence of a sodium peak in EdS analysis, proving the presence of alginate. The EDS spectra peak in both Fu/ZnO-NPs and Fu/ZnO-Alg-NCMs; the O peak appears at 0.5 KeV. Meanwhile, Zn peaks appear at 1 KeV, 8.6 KeV, and 9.5 KeV; these results are in agreement with [62]. Results of EDS spectra approve and verify the XRD result, which reveals the ability of F. vesiculosus marine macroalga to synthesize ZnO-NPs.

TEM Image
The distribution and shape of Fu/ZnO-NPs and Fu/ZnO-Alg-NCMs that were bio-fabricated by brown alga F. vesiculosus were estimated by TEM, as shown in Figure 6. The results showed that Fu/ZnO/Alg-NCMs are spherical, and alginate is a core-shell around the zinc nanoparticles. The size of Fu/ZnO/Alg-NCMs ranged from 12.13 to 19.77 nm Figure 6a. Figure 6b shows the TEM image of Fu/ZnO-NPs, which displays that Fu/ZnO-NPs are rod in shape and size ranging from 12.68 to 17.66 related to width. The Bio-Zn-NPs via Catharanthus roseus are poly-dispersed with a particle size range of 10-20 nm [63]. The Bio-Zn-NPs were fabricated via edible mushrooms, are poly-dispersed with a particle size range of 12-17 nm, and have mostly spherical shapes [64]. TEM results confirmed biosynthesis of ZnO-NPs by Anacardium occidentale was hexagonal with a particle size of 33 nm [65]. According to the TEM image, ZnO-NPs bio-fabricated by pumpkin seeds extract are spherical in shape, with 48-50 nm [66]. ZnO-NPs bio-fabricated via Ulva fasciata were spherical and crystalline with a size range of 3-33 nm a b

TEM Image
The distribution and shape of Fu/ZnO-NPs and Fu/ZnO-Alg-NCMs that were biofabricated by brown alga F. vesiculosus were estimated by TEM, as shown in Figure 6. The results showed that Fu/ZnO/Alg-NCMs are spherical, and alginate is a core-shell around the zinc nanoparticles. The size of Fu/ZnO/Alg-NCMs ranged from 12.13 to 19.77 nm Figure 6a. Figure 6b shows the TEM image of Fu/ZnO-NPs, which displays that Fu/ZnO-NPs are rod in shape and size ranging from 12.68 to 17.66 related to width. The Bio-Zn-NPs via Catharanthus roseus are poly-dispersed with a particle size range of 10-20 nm [63]. The Bio-Zn-NPs were fabricated via edible mushrooms, are poly-dispersed with a particle size range of 12-17 nm, and have mostly spherical shapes [64]. TEM results confirmed biosynthesis of ZnO-NPs by Anacardium occidentale was hexagonal with a particle size of 33 nm [65]. According to the TEM image, ZnO-NPs bio-fabricated by pumpkin seeds extract are spherical in shape, with 48-50 nm [66]. ZnO-NPs bio-fabricated via Ulva fasciata were spherical and crystalline with a size range of 3-33 nm [67]. Polymers 2023, 13, x FOR PEER REVIEW 10 of 17

Zeta Potential Analysis
Results obtained in Figure 8 demonstrate the zeta potential analysis of bio-fabricated Fu/ZnO-NPs and Fu/ZnO/Alg-NCMs bio-fabricated via brown alga F. vesiculosus have negative values (−1.74 and −3.56, respectively). If the value of the zeta potential ranges between 0 and ±5, it is an indicator for rapid coagulation ±10 to ±30, incipient instability ±30 to ±40, moderate stability, ±40 to ±60 good stability, and > ±61 mV excellent stability [71]. So, these results represent the Fu/ZnO-NPs and Fu/ZnO/Alg-NCMs bio-fabricated via brown alga F. vesiculosus are rapid coagulation, as in the TEM image. According to Haider and Mehdi 2014 [72], the zeta potential's negative charge value demonstrates the effectiveness of capping agents in stabilizing AgNPs by indicating more negative charges that keep all the particles apart from one another. Negative values demonstrate the attraction between the particles, leading to a more stable AgNP structure that prevents agglomeration in aqueous solutions [73]. The most frequent Fu/ZnO-Alg-NCMs were 80% at a range size of 10-20 nm. Meanwhile, the most frequent Fu/ZnO-NPs were at 10-20 and 20-30 nm. These results denote that the alginates when capped with ZnO-NPs, changed from rod to spherical in shape and lowered in size (Figure 7a,b). Trandafilovic et al. [68] demonstrated several spherical particles evenly distributed throughout the alginate matrix. The sodium alginate contains evenly dispersed nano-ZnO [69]. The shapes of ZnO/WG (wheat gliadin) nanospheres were nearly spherical [70].

Zeta Potential Analysis
Results obtained in Figure 8 demonstrate the zeta potential analysis of bio-fabricated Fu/ZnO-NPs and Fu/ZnO/Alg-NCMs bio-fabricated via brown alga F. vesiculosus have negative values (−1.74 and −3.56, respectively). If the value of the zeta potential ranges between 0 and ±5, it is an indicator for rapid coagulation ±10 to ±30, incipient instability ±30 to ±40, moderate stability, ±40 to ±60 good stability, and > ±61 mV excellent stability [71]. So, these results represent the Fu/ZnO-NPs and Fu/ZnO/Alg-NCMs bio-fabricated via brown alga F. vesiculosus are rapid coagulation, as in the TEM image. According to Haider and Mehdi 2014 [72], the zeta potential's negative charge value demonstrates the effectiveness of capping agents in stabilizing AgNPs by indicating more negative charges

Zeta Potential Analysis
Results obtained in Figure 8 demonstrate the zeta potential analysis of bio-fabricated Fu/ZnO-NPs and Fu/ZnO/Alg-NCMs bio-fabricated via brown alga F. vesiculosus have negative values (−1.74 and −3.56, respectively). If the value of the zeta potential ranges between 0 and ±5, it is an indicator for rapid coagulation ±10 to ±30, incipient instability ±30 to ±40, moderate stability, ±40 to ±60 good stability, and > ±61 mV excellent stability [71]. So, these results represent the Fu/ZnO-NPs and Fu/ZnO/Alg-NCMs bio-fabricated via brown alga F. vesiculosus are rapid coagulation, as in the TEM image. According to Haider and Mehdi 2014 [72], the zeta potential's negative charge value demonstrates the effectiveness of capping agents in stabilizing AgNPs by indicating more negative charges that keep all the particles apart from one another. Negative values demonstrate the attraction between the particles, leading to a more stable AgNP structure that prevents agglomeration in aqueous solutions [73].

Antibacterial Activities of Fu/ZnO-NPs and Fu/ZnO-Alg-NCMs Bio-Fabricated via Brown Alga F. vesiculosus
The antibacterial activity of Fu/ZnO-NPs and Fu/ZnO-Alg-NCMs bio-synthesized via brown alga F. vesiculosus towards Gram-positive bacteria (Lactobacillus acidophilus CH-2, Streptococcus mutans ATCC 25175, Staphylococcus aureus ATCC6538, Staphylococcus aureus, and Staphylococcus epidermidis), and Gram-negative bacteria (Klebsiella pneumoniae KY856924, Acinetobacter KY856930, E coli KY856932, Enterobacter aerogenes, E coli KY856933 and Enterobacter KY856934) was evaluated by the disc diffusion agar approach (Figures 9-11). Fu/ZnO-NPs were found to have greater antibacterial activity than Fu/ZnO-Alg-NCMs against Gram-negative and Gram-positive bacteria, and there was a significant difference in the effects of both Fu/ZnO-NPs and Fu/ZnO/Alg-NCMs against all tested bacterial strains. Results show that Fu/ZnO/Alg-NCMs had no effect on Staphylococcus epidermidis, Acinetobacter KY856930, and Enterobacter aerogenes, whereas there was an apparent effect of ZnO-NPs against the same strains.
Results demonstrate the Fu/ZnO-NPs have more antibacterial activities than Fu/ZnO/Alg-NCMs. This may be due to alginate polymers that coated zinc oxide nanoparticles and reduced the toxicity of Fu/ZnO-NPs due to poor solubility. By coating nanoparticles with an appropriate polymer, the cytotoxicity of nanoparticles can be reduced since they are less harmful due to their poor solubility and prolonged release [74]. Bakil et al. [75] reported the ZnO incorporated with sodium alginate demonstrated slightly stronger antibacterial effects on Staphylococcus aureus than on E. coli. As a result, sodium alginate (SA)-Zinc oxide (ZnO) nanoparticle has the potential to be used in biomedical applications as a material for wound healing. Bio-fabricated ZnO-NPs may be efficient versus Staphylococcus aureus and Escherichia coli. Moreover, those bio-synthesized by Sargassum wightii inhibited the pathogenic bacteria's growth, including Escherichia coli, Bacillus subtilis, Staphylococcus epidermidis, Salmonella typhi, Enterococcus faecalis, Tyrophyton simii, S. aureus, Aspergillus niger, Cochliobolus lunata, Aspergillus flavus, and Candida albicans [76,77]. The alginate/silica/zinc oxide nano-composite effectively inhibits bacteria [76]. The alginate-montmorillonite/lemon essential oil nano-composite was more effective versus Gram-positive bacteria (Bacillus cereus and Bacillus aureus) than a b The antibacterial activity of Fu/ZnO-NPs and Fu/ZnO-Alg-NCMs bio-synthesized via brown alga F. vesiculosus towards Gram-positive bacteria (Lactobacillus acidophilus CH-2, Streptococcus mutans ATCC 25175, Staphylococcus aureus ATCC6538, Staphylococcus aureus, and Staphylococcus epidermidis), and Gram-negative bacteria (Klebsiella pneumoniae KY856924, Acinetobacter KY856930, E coli KY856932, Enterobacter aerogenes, E coli KY856933 and Enterobacter KY856934) was evaluated by the disc diffusion agar approach (Figures 9-11). Fu/ZnO-NPs were found to have greater antibacterial activity than Fu/ZnO-Alg-NCMs against Gram-negative and Gram-positive bacteria, and there was a significant difference in the effects of both Fu/ZnO-NPs and Fu/ZnO/Alg-NCMs against all tested bacterial strains. Results show that Fu/ZnO/Alg-NCMs had no effect on Staphylococcus epidermidis, Acinetobacter KY856930, and Enterobacter aerogenes, whereas there was an apparent effect of ZnO-NPs against the same strains.
Results demonstrate the Fu/ZnO-NPs have more antibacterial activities than Fu/ZnO/Alg-NCMs. This may be due to alginate polymers that coated zinc oxide nanoparticles and reduced the toxicity of Fu/ZnO-NPs due to poor solubility. By coating nanoparticles with an appropriate polymer, the cytotoxicity of nanoparticles can be reduced since they are less harmful due to their poor solubility and prolonged release [74]. Bakil et al. [75] reported the ZnO incorporated with sodium alginate demonstrated slightly stronger antibacterial effects on Staphylococcus aureus than on E. coli. As a result, sodium alginate (SA)-Zinc oxide (ZnO) nanoparticle has the potential to be used in biomedical applications as a material for wound healing. Bio-fabricated ZnO-NPs may be efficient versus Staphylococcus aureus and Escherichia coli. Moreover, those bio-synthesized by Sargassum wightii inhibited the pathogenic bacteria's growth, including Escherichia coli, Bacillus subtilis, Staphylococcus epidermidis, Salmonella typhi, Enterococcus faecalis, Tyrophyton simii, S. aureus, Aspergillus niger, Cochliobo-lus lunata, Aspergillus flavus, and Candida albicans [76,77]. The alginate/silica/zinc oxide nano-composite effectively inhibits bacteria [76]. The alginate-montmorillonite/lemon essential oil nano-composite was more effective versus Gram-positive bacteria (Bacillus cereus and Bacillus aureus) than Gram-negative bacteria (Staphylococcus enteritis and Escherichia coli) [78]. The ZnO-Alginate nano-composite demonstrated the most significant reduction activity versus Staphylococcus aureus and Escherichia coli [55,57]. In addition, Zinc oxide-sodium alginate-cellulose nano-composite fibers (ZnO-SACNF) showed exceptional antibacterial activity against E. coli [79]. Figure 12 demonstrates the possible mechanisms of ZnO-NPs against bacteria due to the distraction of the cell membrane, binding to DNA and proteins, and generation of reactive oxygen species (ROS) [80]. After 15 min of bacterial cell exposure to the ZnO-NPs, 70% of the cytoplasmic membrane was damaged [81]. The mechanisms of ZnO-NPs as antibacterial, including the incorporation of NPs due to loss of proton motive force, internalization of cell walls due to ZnO-localized contact, increased membrane permeability, and ingestion of hazardous dissolved zinc ions, have been greatly influenced by ROS. These have resulted in mitochondrial weakening, intracellular leakage, and oxidative stress gene expression that eventually inhibited cell development and caused cell death [82]. At low doses, ZnO nanoparticles showed deadly effects on Campylobacter jejuni and impressive antibacterial activity. Considerable morphological alterations, detectable membrane leakage, and considerable elevations (up to 52-fold) in oxidative stress gene expression were all brought on by ZnO nanoparticles in Campylobacter jejuni. ZnO alters the permeability of the membranes through which nanoparticles penetrate and cause oxidative stress in bacterial cells, which ultimately leads to cell death [83].
Polymers 2023, 13, x FOR PEER REVIEW activity against E. coli [79]. Figure 12 demonstrates the possible mechanisms of Zn against bacteria due to the distraction of the cell membrane, binding to DNA an teins, and generation of reactive oxygen species (ROS) [80]. After 15 min of bacte exposure to the ZnO-NPs, 70% of the cytoplasmic membrane was damaged [8 mechanisms of ZnO-NPs as antibacterial, including the incorporation of NPs due of proton motive force, internalization of cell walls due to ZnO-localized cont creased membrane permeability, and ingestion of hazardous dissolved zinc ion been greatly influenced by ROS. These have resulted in mitochondrial weaken tracellular leakage, and oxidative stress gene expression that eventually inhibi development and caused cell death [82]. At low doses, ZnO nanoparticles showed effects on Campylobacter jejuni and impressive antibacterial activity. Considerab phological alterations, detectable membrane leakage, and considerable elevations 52-fold) in oxidative stress gene expression were all brought on by ZnO nanopar Campylobacter jejuni. ZnO alters the permeability of the membranes through wh noparticles penetrate and cause oxidative stress in bacterial cells, which ultimatel to cell death [83].

Conclusions
The current work demonstrated brown alga Fucs. vesiculosus is a good candidat the synthesis of Fu/ZnO-NPs and Fu/Alg-ZnO-NCMs, confirmed by FT-IR. The res by XRD, zeta potential, and TEM demonstrate Fu/ZnO-NPs are crystalline, rod-sha and have a negative charge. Fu/Alg-ZnO-NCMs are semi-crystalline, spherical, and h more negative charge than Fu/ZnO-NPs. The peak of Zn (EDS analysis) appears in Fu/ZnO-NPs and Fu/Alg-ZnO-NCMs at 1 KeV, 8.6 KeV, and 9.5 KeV and proves the rity of Fu/ZnO-NPs. The change in shape, charge, and crystalline in Fu/Alg-ZnO-NC is due to alginate that acts as a capping agent of Fu/ZnO-NPs. Fu/ZnO-NPs have the antibacterial activities against MDR bacterial strains (Streptococcus mutans ATCC 25 Lactobacillus acidophilus CH-2, Staphylococcus aureus ATCC6538; Staphylococcus epiderm

Conclusions
The current work demonstrated brown alga Fucs. vesiculosus is a good candidate for the synthesis of Fu/ZnO-NPs and Fu/Alg-ZnO-NCMs, confirmed by FT-IR. The results by XRD, zeta potential, and TEM demonstrate Fu/ZnO-NPs are crystalline, rod-shaped, and have a negative charge. Fu/Alg-ZnO-NCMs are semi-crystalline, spherical, and have more negative charge than Fu/ZnO-NPs. The peak of Zn (EDS analysis) appears in both Fu/ZnO-NPs and Fu/Alg-ZnO-NCMs at 1 KeV, 8.6 KeV, and 9.5 KeV and proves the purity of Fu/ZnO-NPs. The change in shape, charge, and crystalline in Fu/Alg-ZnO-NCMs is due to alginate that acts as a capping agent of Fu/ZnO-NPs. Fu/ZnO-NPs have the best antibacterial activities against MDR bacterial strains (Streptococcus mutans ATCC 25175; Lactobacillus acidophilus CH-2, Staphylococcus aureus ATCC6538; Staphylococcus epidermidis; Staphylococcus aureus, Klebsiella pneumoniae KY856924: Acinetobacter KY856930; E coli KY856932; Enterobacter aerogenes; E coli KY856933; Enterobacter KY856934), then that was coated with alginate (Fu/Alg-ZnO-NCMs).